1. Field of the Invention
The present invention relates to a focus method and a photographic device. More particularly, the present invention relates to a focus method and a photographic device that can focus fast and precisely.
2. Description of the Related Art
In existing technology, an S0 continuous focus mode of a digital camera is used to calculate contrast values of a farther position and a closer position relative to a present position, and the contrast value represents the clearness of an image. If the present position has the highest contrast value, which indicates that an accurate focus position is within a scanning area, the photographic device applies a polynomial approximation method to calculate the accurate focus position. If the farther position or the closer position has the highest contrast value, the photographic device continues to calculate the position which is farther than the farther position or closer than the closer position relative to the photographic device until the contrast value decreases. The photographic device applies a polynomial approximation method to calculate the accurate focus position. When the photographic device detects the accurate focus position, the photographic device records the contrast value of the accurate focus position in order to identify whether the accurate focus position has changed or not. If the accurate focus position has changed, the photographic device launches the S0 continuous focus mode again, and if the accurate focus position has not changed, the photographic device does not perform anything.
When the photographic device detects the accurate focus position, the photographic device applies a moving interval. However, whether the photographic device applies a longer or a shorter moving interval, there are drawbacks. A longer moving interval will cause unstable vibration and resultant imprecise focusing. A shorter moving interval causes slow focusing, especially in the case of a great difference between the beginning position and the accurate focus position. Because it takes time to acquire each of the frames in the S0 continuous focus mode, focusing at a long distance consumes a great amount of time.
Therefore, there is a need to provide a method for arranging schedules and a computer using the same to mitigate and/or obviate the aforementioned problems.